Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “Basins and Coasts”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
USGS2005

Biology and invasive species in the western U.S

The diversity of environments that characterizes the West is responsible for the region's rich biological heritage. This ecological diversity also means that opportunities for invasive species are many, varied, and complex. Island ecosystems are notoriously vulnerable to invaders as demonstrated in Hawaii and West Coast offshore islands. Aquatic invaders impose high economic and environmental costs in systems as varied as San Francisco Bay and desert springs in the Great Basin. Although the West's arid and montane ecosystems may seem resistant to plant and animal invaders, we now know that ex-otic species have altered physical processes related to fire and hydrology in a manner favoring further expansion and persis-tence of invaders. Natural resource managers value analytical, mapping, and genetics tools developed by USGS scientists to monitor invasive species and help conserve biological systems. USGS biologists conduct research to assist land and water managers' efforts to control invasive species and restore natural systems. Throughout the West, the USGS carries out studies for early detection and rapid assessment of invaders. The following are some examples of how the USGS is making a difference in the western United States.

Fact Sheet↗
USGS1978

A gravity study of the northern part of the Arctic National Wildlife Range, Alaska

Interpretation of all publicly available onshore gravity data provides a basis for outlining regional elements of the basement and overlying structure in the northern part of the Arctic National Wildlife Range. Major post-Carboniferous sedimentary basins whose centers lie offshore on the Beaufort Shelf extend onshore in the northern part of the study area. There is strong evidence that dense basement rocks beneath these onshore extensions rise to relatively shallow depths along the northeast Alaskan coast. Geologic studies and interpretation of the gravity data indicate that the gross structural and stratigraphic framework of this area is similar to that of the Prudhoe Bay region to the west. A high potential for petroleum accumulation in the Wildlife Range is indicated by the surface presence of oil seeps, oil sands, and outcrops of reservoir and source rocks along the southern margins of the onshore basinal areas. Present data suggest that the greatest potential for onshore accumulations of hydrocarbons lies in the area south and east of Barter Island and that possibilities exist there for commercially substantial reserves. The potential of this area cannot be fully assessed, however, until the subsurface extent of several major unconformities is known. Unfortunately, gravity data alone are of little use in such determinations. South of the mountain front, large granitic intrusions are marked by a sharply defined gravity minimum. The subsurface distribution of these bodies could probably be mapped by detailed gravity surveys. Detailed aeromagnetic surveys should serve equally well for such a purpose.

Alaska↗
USGS2007

Aeromagnetic anomaly patterns reveal buried faults along the eastern margin of the Wilkes Subglacial Basin (East Antarctica)

The Wilkes Subglacial Basin (WSB) is the major morphological feature recognized in the hinterland of the Transantarctic Mountains. The origin of this basin remains contentious and relatively poorly understood due to the lack of extensive geophysical exploration. We present a new aeromagnetic anomaly map over the transition between the Transantarctic Mountains and the WSB for an area adjacent to northern Victoria Land. The aeromagnetic map reveals the existence of subglacial faults along the eastern margin of the WSB. These inferred faults connect previously proposed fault zones over Oates Land with those mapped along the Ross Sea Coast. Specifically, we suggest a link between the Matusevich Frature Zone and the Priestley Fault during the Cenozoic. The new evidence for structural control on the eastern margin of the WSB implies that a purely flexural origin for the basin is unlikely.

Open-File Report↗
USGS2026

Evaluation of pathogen risks and testing considerations for Chinook salmon egg movements between New Zealand and California

Executive Summary Oncorhynchus tshawytscha (Walbaum in Artedi, 1792; Chinook salmon) were historically abundant in the McCloud River but are now extirpated from this tributary owing to dam construction and lack of passage. Planning efforts to restore populations above Shasta and Keswick Dams are currently underway, including an evaluation of potential source populations. One potential source is New Zealand Chinook salmon, which are believed to have originated from tributaries of the Sacramento River. These fish could be returned to California if reintroduction risks, including risks of pathogen introduction, could be sufficiently mitigated. The U.S. Geological Survey was contracted to provide scientific support for reintroduction efforts, including evaluating the risks of pathogen transmission via the movement of Chinook salmon eggs from New Zealand to the McCloud River. This report estimates pathogen risks associated with egg movement and considers epidemiological and biosecurity measures to minimize these risks. Pathogen risks associated with the movement of Chinook salmon eggs from New Zealand were evaluated based on pathogen virulence, transmission route, and geographic distribution. These criteria identified 14 moderate- and high-risk pathogens out of the 30 pathogens evaluated. Pathogen species and strains were considered high risk if they have the potential for vertical transmission (that is, transmission from parent to offspring), are moderately or highly virulent, and are exotic to the Sacramento River Basin. According to these criteria, we identified the following pathogens as high risk: New Zealand rickettsia-like organisms 1 and 2. —These bacterial pathogens have been associated with mortality events in farmed Chinook salmon from the South Island of New Zealand but have not been detected in other regions. Pilchard orthomyxovirus (POMV). —POMV has been detected in Sardina pilchardus (Walbaum, 1792; pilchards) and Salmo salar (Linnaeus, 1758; Atlantic salmon) from the coasts of southern Australia and Tasmania. POMV can cause relatively high mortality rates and may be indirectly transmitted via contaminated water sources. Infectious pancreatic necrosis virus (IPNV). —IPNV has a wide geographic distribution and is present in the Sacramento River Basin, but the IPNV-like viruses detected in Australia and New Zealand are unique from those found in the United States. Yersinia ruckeri . —This bacterial pathogen is the causative agent of enteric redmouth disease and has a widespread geographic distribution. However, the strains that are present in Australia and New Zealand are unique from those found in North America. Strategic use of testing and biosecurity measures can minimize pathogen risks associated with the movement of eggs. The most effective measures include iodophor treatment of eggs to remove external pathogens, testing of all the adult fish from which gametes are obtained, and a quarantine period after transport to confirm pathogen testing results. Additional measures to enhance biosecurity could include testing the quarantined fish following emergence and (or) developing a fish health history of the source population through pathogen monitoring.

California↗
USGS1981

Suspected Great Blue Heron population decline after a severe winter in the Columbia Basin

The wintering range of the Great Blue Heron ( Ardea herodias ) extends further north than does that of any other member of the Ciconiiformes in North America. The northern limits of its range extend along the Pacific coast into southeastern Alaska, into Massachusetts on the Atlantic coast, and inland into southern Montana (Palmer 1962). In the northern part of its range, severe winter weather may persist for weeks or months. Little information is available regarding either the response of individual Great Blue Herons to severe winters or the effects of these conditions on populations. In this paper, we report our observations on a small heron population in Oregon and Washington that was exposed to a severe winter.

Oregon, Washington↗
USGS2013

Geographic variation in migration chronology and winter distribution of midcontinent greater white-fronted geese

We evaluated spatial and temporal differences in migratory behavior among different breeding groups of midcontinent greater white-fronted geese (Anser albifrons) using band-recovery data and observations of neck collared geese during migration and winter. Birds from different breeding areas were initially delineated by geographic distance into 6 banding reference areas (BRAs): 1) interior Alaska, 2) North Slope of Alaska, 3) western Northwest Territories (NWT), 4) western Nunavut, 5) central Nunavut, and 6) eastern Nunavut. The banding groups also differed by breeding habitat, with geese from interior Alaska nesting in the boreal forest (taiga), and all other groups breeding in tundra habitats. Geese from interior Alaska migrated earlier during autumn, and were more likely to winter farther south (in Mexico) than geese from other breeding areas. Geese banded in central and eastern Nunavut (Queen Maud Gulf and Inglis River) wintered farther east (in Louisiana) than geese from other breeding areas. Small-scale (within-state) geographic segregation of wintering flocks was evidenced by the recent (post-1990) nearly exclusive use of a new wintering area in north central Texas by geese from interior Alaska. Segregation among BRAs was also apparent in Mexico, where taiga geese were found predominantly in the central Highlands (states of Zacatecas and Durango), whereas tundra geese mostly used states along the Gulf Coast (primarily Tamaulipas). Interior Alaska birds initiated spring migration earlier than geese from other areas, and were more likely than others to stop in the Rainwater Basin of Nebraska, a region where cholera outbreaks periodically kill thousands of geese. Geese from interior Alaska were the first to arrive at spring staging areas in prairie Canada where BRAs exhibited spatial delineation (a longitudinal cline) in relation to breeding areas. Our results show significant geographic and temporal variation among taiga and tundra breeding cohorts during autumn, winter, and spring. Temporal and spatial differences in migratory behavior may allow management practices that accommodate potential demographic differences between taiga and tundra populations.

Journal of Wildlife Management↗
USGS2012

Geologic assessment of undiscovered conventional oil and gas resources--Middle Eocene Claiborne Group, United States part of the Gulf of Mexico Basin

The Middle Eocene Claiborne Group was assessed using established U.S. Geological Survey (USGS) assessment methodology for undiscovered conventional hydrocarbon resources as part of the 2007 USGS assessment of Paleogene-Neogene strata of the United States part of the Gulf of Mexico Basin including onshore and State waters. The assessed area is within the Upper Jurassic-Cretaceous-Tertiary Composite total petroleum system, which was defined as part of the assessment. Source rocks for Claiborne oil accumulations are interpreted to be organic-rich downdip shaley facies of the Wilcox Group and the Sparta Sand of the Claiborne Group; gas accumulations may have originated from multiple sources including the Jurassic Smackover and Haynesville Formations and Bossier Shale, the Cretaceous Eagle Ford and Pearsall(?) Formations, and the Paleogene Wilcox Group and Sparta Sand. Hydrocarbon generation in the basin started prior to deposition of Claiborne sediments and is ongoing at present. Emplacement of hydrocarbons into Claiborne reservoirs has occurred primarily via vertical migration along fault systems; long-range lateral migration also may have occurred in some locations. Primary reservoir sands in the Claiborne Group include, from oldest to youngest, the Queen City Sand, Cook Mountain Formation, Sparta Sand, Yegua Formation, and the laterally equivalent Cockfield Formation. Hydrocarbon traps dominantly are rollover anticlines associated with growth faults; salt structures and stratigraphic traps also are important. Sealing lithologies probably are shaley facies within the Claiborne and in the overlying Jackson Group. A geologic model, supported by spatial analysis of petroleum geology data including discovered reservoir depths, thicknesses, temperatures, porosities, permeabilities, and pressures, was used to divide the Claiborne Group into seven assessment units (AU) with distinctive structural and depositional settings. The AUs include (1) Lower Claiborne Stable Shelf Gas and Oil (50470120), (2) Lower Claiborne Expanded Fault Zone Gas (50470121), (3) Lower Claiborne Slope and Basin Floor Gas (50470122), (4) Lower Claiborne Cane River (50470123), (5) Upper Claiborne Stable Shelf Gas and Oil (50470124), (6) Upper Claiborne Expanded Fault Zone Gas (50470125), and (7) Upper Claiborne Slope and Basin Floor Gas (50470126). Total estimated mean undiscovered conventional hydrocarbon resources in the seven assessment units combined are 52 million barrels of oil, 19.145 trillion cubic feet of natural gas, and 1.205 billion barrels of natural gas liquids. A recurring theme that emerged from the evaluation of the seven Claiborne AUs is that the great bulk of undiscovered hydrocarbon resources comprise non-associated gas and condensate contained in deep (mostly >12,000 feet), overpressured, structurally complex outer shelf or slope and basin floor reservoirs. The continuing development of these downdip objectives is expected to be the primary focus of exploration activity for the onshore Middle Eocene Gulf Coast in the coming decades.

Arkansas;Alabama;Florida;Georgia;Kentucky;Louisian↗
USGS1969

A ground-water reconnaissance of the Republic of Ghana, with a description of geohydrologic provinces

This report gives a general summary of the availability and use of ground water and describes the occurrence of ground water in five major geohydrologic provinces lying in the eight administrative regions of Ghana. The identification and delineation of the geohydrologic provinces are based on their distinctive characteristics with respect to the occurrence and availability of ground water. The Precambrian province occupies the southern, western, and northern parts of Ghana and is underlain largely by intrusive crystalline and metasedimentary rocks. The Voltaian province includes that part of the Voltaian sedimentary basin in central Ghana and is underlain chiefly by consolidated sandstone, mudstone, and shale. Narrow discontinuous bands of consolidated Devonian and Jurassic sedimentary rocks near the coast constitute the Coastal Block Fault province. The Coastal Plain province includes semiconsolidated to unconsolidated sediments of Cretaceous to Holocene age that underlie coastal plain areas in southwestern and southeastern Ghana. The Alluvial province includes the Quaternary alluvial deposits in the principal river valleys and on the delta of the Volta River. Because of the widespread distribution of crystalline and consolidated sedimentary rocks of low permeability in the Precambrian, Voltaian, and Coastal Block Fault provinces, it is difficult to develop large or event adequate groundwater supplies in much of Ghana. On the other hand, small (1 to 50 gallons per minute) supplies of water of usable quality are available from carefully sited boreholes in most parts of the country. Also, moderate (50 to 200 gpm) supplies of water are currently (1964) obtained from small-diameter screened boreholes tapping sand and limestone aquifers in the Coastal Plain province in southwestern and southeastern Ghana, but larger supplies could be obtained through properly constructed boreholes. In the Alluvial province, unconsolidated deposits in the larger stream valleys that are now largely undeveloped offer desirable locations for shallow vertical or horizontal wells, which can induce infiltration from streams and yield moderate to large water supplies. The principal factors that limit development of ground-water supplies in Ghana are (1) prevailing low permeability and water-yielding potential of the crystalline and consolidated sedimentary rocks that underlie most of the country, (2) highly mineralized ground water which appears to be widely distributed in the northern part of the Voltaian province, and (3) potential problems of salt-water encroachment in the Coastal Plain province in the Western Region and in the Keta area. On the other hand, weathering has increased porosity and has thus substantially increased the water-yielding potential of the crystalline and consolidated sedimentary rocks in much of central and northern Ghana. Also, with proper construction and development, much larger yields than those now (1964) prevalent could be obtained from boreholes tapping sand and limestone aquifers in the Coastal Plain province.

Water Supply Paper↗
USGS1979

The gravity field of the U.S. Atlantic continental margin

Approximately 39,000 km of marine gravity data collected during 1975 and 1976 have been integrated with U.S. Navy and other available data over the U.S. Atlantic continental margin between Florida and Maine to obtain a 10 mgal contour free-air gravity anomaly map. A maximum typically ranging from 0 to +70 mgal occurs along the edge of the shelf and Blake Plateau, while a minimum typically ranging from −20 to −80 mgal occurs along the base of the continental slope, except for a −140 mgal minimum at the base of the Blake Escarpment. Although the maximum and minimum free-air gravity values are strongly influenced by continental slope topography and by the abrupt change in crustal thickness across the margin, the peaks and troughs in the anomalies terminate abruptly at discrete transverse zones along the margin. These zones appear to mark major NW—SE fractures in the subsided continental margin and adjacent deep ocean basin, which separate the margin into a series of segmented basins and platforms. Rapid differential subsidence of crustal blocks on either side of these fractures during the early stages after separation of North America and Africa (Jurassic and Early Cretaceous) is inferred to be the cause of most of the gravity transitions along the length of margin. The major transverse zones are southeast of Charleston, east of Cape Hatteras, near Norfolk Canyon, off Delaware Bay, just south of Hudson Canyon and south of Cape Cod. Local Airy isostatic anomaly profiles (two-dimensional, without sediment corrections) were computed along eight multichannel seismic profiles. The isostatic anomaly values over major basins beneath the shelf and rise are generally between −10 and −30 mgal while those over the platform areas are typically 0 to +20 mgal. While a few isostatic anomaly profiles show local 10–20 mgal increases seaward of the East Coast Magnetic Anomaly (ECMA: inferred to mark the ocean-continent boundary), the lack of a consistent correlation indicates that the relationship of isostatic gravity anomalies to the magnetic anomalies and the ocean—continent transition is variable. Two-dimensional gravity models have been computed for two profiles off Cape Cod, Massachusetts and Cape May, New Jersey, where excellent reflection, refraction and magnetic control appear to define 10 and 12 km deep sedimentary basins beneath the shelf, respectively and 10 km deep basins beneath the rise. The basins are separated by a 6–8 km deep basement ridge which underlies the ECMA and appears to mark the landward edge of oceanic crust. The gravity models suggest that the oceanic crust is between 11 and 18 km thick beneath the ECMA, but decreases to a thickness of less than 8 km within the first 20–90 km to the southeast. In both profiles, the derived crustal thickness variations support the interpretation that the ECMA occurs over the ocean-continent boundary. The crust underlying the sedimentary cover appears to be 12 to 15 km thick on the landward side of the ECMA and gradually thickens to normal continental values of greater than 25 km within the first 60 to 110 km to the northwest. Multichannel seismic profiles across platform areas, such as Cape Hatteras and Cape Cod, indicate the ocean-continent transition zones there are much narrower than profiles across major sedimentary basins, such as the one off New Jersey.

Tectonophysics↗
USGS2013

Geomorphic and vegetation processes of the Willamette River floodplain, Oregon: current understanding and unanswered science questions

This report summarizes the current understanding of floodplain processes and landforms for the Willamette River and its major tributaries. The area of focus encompasses the main stem Willamette River above Newberg and the portions of the Coast Fork Willamette, Middle Fork Willamette, McKenzie, and North, South and main stem Santiam Rivers downstream of U.S. Army Corps of Engineers dams. These reaches constitute a large portion of the alluvial, salmon-bearing rivers in the Willamette Basin. The geomorphic, or historical, floodplain of these rivers has two zones - the active channel where coarse sediment is mobilized and transported during annual flooding and overbank areas where fine sediment is deposited during higher magnitude floods. Historically, characteristics of the rivers and geomorphic floodplain (including longitudinal patterns in channel complexity and the abundance of side channels, islands and gravel bars) were controlled by the interactions between floods and the transport of coarse sediment and large wood. Local channel responses to these interactions were then shaped by geologic features like bedrock outcrops and variations in channel slope. Over the last 150 years, floods and the transport of coarse sediment and large wood have been substantially reduced in the basin. With dam regulation, nearly all peak flows are now confined to the main channels. Large floods (greater than 10-year recurrence interval prior to basinwide flow regulation) have been largely eliminated. Also, the magnitude and frequency of small floods (events that formerly recurred every 2–10 years) have decreased substantially. The large dams trap an estimated 50–60 percent of bed-material sediment—the building block of active channel habitats—that historically entered the Willamette River. They also trap more than 80 percent of the estimated bed material in the lower South Santiam River and Middle and Coast Forks of the Willamette River. Downstream, revetments further decrease bed-material supply by an unknown amount because they limit bank erosion and entrainment of stored sediment. The rivers, geomorphic floodplain, and vegetation within the study area have changed noticeably in response to the alterations in floods and coarse sediment and wood transport. Widespread decreases have occurred in the rates of meander migration and avulsions and the number and diversity of landforms such as gravel bars, islands, and side channels. Dynamic and, in some cases, multi-thread river segments have become stable, single-thread channels. Preliminary observations suggest that forest area has increased within the active channel, further reducing the area of unvegetated gravel bars. Alterations to floods and sediment transport and ongoing channel, floodplain, and vegetation responses result in a modern Willamette River Basin. Here, the floodplain influenced by the modern flow and sediment regimes, or the functional floodplain, is narrower and inset with the broader and older geomorphic floodplain. The functional floodplain is flanked by higher elevation relict floodplain features that are no longer inundated by modern floods. The corridor of present- day active channel surfaces is narrower, enabling riparian vegetation to establish on formerly active gravel bar surfaces. The modern Willamette River Basin with its fundamental changes in the flood, sediment transport, and large wood regimes has implications for future habitat conditions. System-wide future trends probably include narrower floodplains and a lower diversity of landforms and habitats along the Willamette River and its major tributaries compared to historical patterns and today. Furthermore, specific conditions and future trends will probably vary between geologically stable, anthropogenically stable, and dynamic reaches. The middle and lower segments of the Willamette River are geologically stable, whereas the South Santiam and Middle Fork Willamette Rivers were historically dynamic, but are now largely stable in response to flow regulation and revetment construction. The upper Willamette and North Santiam Rivers retain some dynamic characteristics, and provide the greatest diversity of aquatic and riparian habitats under the current flow and sediment regime. The McKenzie River has some areas that are more dynamic, whereas other sections are stable due to geology or revetments. Historical reductions in channel dynamism also have implications for ongoing and future recruitment and succession of floodplain forests. For instance, the succession of native plants like black cottonwood is currently limited by (1) fewer low-elevation gravel bars for stand initiation; (2) altered streamflow during seed release, germination, and stand initiation; (3) competition from introduced plant species; and (4) frequent erosion of young vegetation in some locations because scouring flows are concentrated within a narrow channel corridor. Despite past alterations, the Willamette River Basin has many of the physical and ecological building blocks necessary for highly functioning rivers. Management strategies, including environmental flow programs, river and floodplain restoration, revetment modifications, and reclamation of gravel mines, are underway to mitigate some historical changes. However, there are some substantial gaps in the scientific understanding of the modern Willamette basin that is needed to efficiently integrate these blocks and to establish realistic objectives for future conditions. Unanswered questions include: 1. What is the distribution and diversity of landforms and habitats along the Willamette River and its tributaries? 2. What is the extent of today’s functional floodplain—the part of the river corridor actively formed and modified by fluvial processes? 3. How are landforms and habitats in the Willamette River Basin created and sustained by present-day flow and sediment conditions? 4. How is the succession of native floodplain vegetation shaped by present-day flow and sediment conditions? Answering these questions will produce baseline data on the current distributions of landforms and habitats (question 1), the extent of the functional floodplain (question 2), and the effects of modern flow and sediment regimes on future floodplain landforms, habitats, and vegetation succession (questions 3 and 4). Addressing questions 1 and 2 is a logical next step because they underlie questions 3 and 4. Addressing these four questions would better characterize the modern Willamette Basin and help in implementing and setting realistic targets for ongoing management strategies, demonstrating their effectiveness at the site and basin scales, and anticipating future trends and conditions.

Oregon↗
USGS2010

Assessment of undiscovered conventional oil and gas resources, onshore Claiborne Group, United Statespart of the northern Gulf of Mexico Basin

The middle Eocene Claiborne Group was assessed for undiscovered conventional hydrocarbon resources using established U.S. Geological Survey assessment methodology. This work was conducted as part of a 2007 assessment of Paleogene-Neogene strata of the northern Gulf of Mexico Basin, including the United States onshore and state waters (Dubiel et al., 2007). The assessed area is within the Upper Jurassic-CretaceousTertiary composite total petroleum system, which was defined for the assessment. Source rocks for Claiborne oil accumulations are interpreted to be organic-rich, downdip, shaley facies of the Wilcox Group and the Sparta Sand of the Claiborne Group; gas accumulations may have originated from multiple sources, including the Jurassic Smackover Formation and the Haynesville and Bossier shales, the Cretaceous Eagle Ford and Pearsall (?) formations, and the Paleogene Wilcox Group and Sparta Sand. Hydrocarbon generation in the basin started prior to deposition of Claiborne sediments and is currently ongoing. Primary reservoir sandstones in the Claiborne Group include, from oldest to youngest, the Queen City Sand, Cook Mountain Formation, Sparta Sand, Yegua Formation, and the laterally equivalent Cockfield Formation. A geologic model, supported by spatial analysis of petroleum geology data, including discovered reservoir depths, thicknesses, temperatures, porosities, permeabilities, and pressures, was used to divide the Claiborne Group into seven assessment units (AUs) with three distinctive structural and depositional settings. The three structural and depositional settings are (1) stable shelf, (2) expanded fault zone, and (3) slope and basin floor; the seven AUs are (1) lower Claiborne stable-shelf gas and oil, (2) lower Claiborne expanded fault-zone gas, (3) lower Claiborne slope and basin-floor gas, (4) lower Claiborne Cane River, (5) upper Claiborne stable-shelf gas and oil, (6) upper Claiborne expanded fault-zone gas, and (7) upper Claiborne slope and basin-floor gas. Based on Monte Carlo simulation of justified input parameters, the total estimated mean undiscovered conventional hydrocarbon resources in the seven AUs combined are 52 million bbl of oil, 19.145 tcf of natural gas, and 1.205 billion bbl of natural gas liquids. This article describes the conceptual geologic model used to define the seven Claiborne AUs, the characteristics of each AU, and the justification behind the input parameters used to estimate undiscovered resources for each AU. The great bulk of undiscovered hydrocarbon resources are predicted to be nonassociated gas and natural gas liquids contained in deep (mostiy >12,000-ft [3658 m], present-day drilling depths), overpressured, structurally complex outer shelf or slope and basin-floor Claiborne reservoirs. The continuing development of these downdip objectives is expected to be the primary focus of exploration activity for the onshore middle Eocene Gulf Coast in the coming decades. ?? 2010 U.S. Geological Survey. All rights reserved.

American Association of Petroleum Geologists Bulle↗
USGS1976

Evidence of post-Pleistocene faults on New Jersey Atlantic outer continental shelf

Recently obtained high-resolution seismic profiles (400-4,000-Hz band) show evidence of faults in shallow sedimentary strata near the edge of the Atlantic continental shelf off New Jersey. Apparent normal faults having a throw of about 1.5 m displace sediments to within 7 m of the sea floor. The faults appear to be overlain by undeformed horizontal beds of relatively recent age. Several faults 1 to 2 km apart strike approximately N70°E and dip northwest. The data suggest that the faults are upthrown on the southeast. Projection of the faults on the high-resolution profiles to a nearby multichannel seismic-reflection profile indicates that these shallow faults might be the near-surface expression of a more fundamental deep-seated fault. Several prominent reflectors in the multichannel records are offset by a high-angle normal fault reaching depths of 4.0 to 5.0 sec (6.0 to 6.5 km). The deep fault on the multichannel line also is upthrown on the southeast. Throws of as much as 90 m are apparent at depth, but offsets of as much as 10 m could be present in the shallower parts of the section that may not be resolved in the multichannel data. The position and strike of these faults coincide with and parallel the East Coast magnetic anomaly interpreted as the fundamental seaward basement boundary of the Baltimore Canyon trough. Recurring movements along such boundary faults are expected theoretically if the marginal basins are subsiding in response to the plate rotation of North America and seafloor spreading in the Atlantic.

New Jersey↗
USGS1979

Ground-water monitoring at Santa Barbara, California: Phase 1— Coastal monitor-well installation and initial measurements

Plans to reduce natural ground-water storage in the 7-square-mile Santa Barbara groundwater basin have caused concern about possible saltwater intrusion into the coastal freshwater aquifer. To give advance warning of such intrusion, two multipiezometer wells were installed along the coast, about half a mile and 1 mile from the pumping center. Each site contains four small-diameter wells, completed at depths between 95 and 800 feet, which monitor water levels and water quality in (1) the shallow zone above the producing zones, (2) the upper producing zone, (3) the lower producing zone, and (4) the deep zone below the producing zones. The wells were measured and sampled initially in September 1978 during a 2-million gallons per day pumping phase of the municipal supply wells. In the eight samples collected, dissolved-solids concentrations ranged from 450 to 6,290 mg/L and chloride concentrations ranged from 35 to 2,800 mg/L. At the site farther from the center of pumping , the well monitoring the upper producing zone was the only one with a water level below sea level, and it produced the water of poorest quality. At the site nearer the center of pumping, water levels in both producing zones and the deep zone were between 2 and 18 feet below sea level, with the water of poorest quality occurring in the lower producing zone. Although the dissolved-solids concentrations are high in several zones, the potential for saltwater intrusion can be reliably evaluated only after analysis of long-term records. (Woodard-USGS)

California↗
USGS2023

Storm and tsunami overwash sediment transport inferred from recent deposits

Overwash deposits from storms and tsunamis record information about sediment transport and flow that can be used to inform hazard assessments. Here we explore deposits from two extreme wave events: (1) the 2012 Hurricane Sandy, a Category 5 hurricane that is the largest storm in the Atlantic basin on historical record, and (2) the 2011 Tohoku-oki tsunami, created by a 9.0 Mw earthquake, that was up to 20 m high at the coast.

Conference Paper↗
USGS1993

Beach profile modification and sediment transport by ice: an overlooked process on Lake Michigan

Coastal lake ice includes a belt of mobile crash and slush ice and a stable nearshore-ice complex (NIC). Sediment concentrations indicate that the NIC and the belt of brash and slush contains 180 to 280 t (113 to 175m3) of sand per kilometer of coast. This static sediment load is roughly equivalent to the average amount of sand eroded from the bluffs and to the amount accumulating in the deep lake basin each year. Sediment is being rafted alongshore in the mobile brash and slush at rates of 10 to 30 cm/sec. -from Authors

Journal of Coastal Research↗
USGS2011

Fire in the Mediterranean Basin

The Mediterranean Basin is a meeting point of three continents, Europe, Asia and Africa, and this is responsible for the great diversity of plants, animals and cultures that formed the cradle of Western civilization. It is considered one of the biodiversity hotspots (Myers et al . 2000) because of its high species richness and high proportion of endemisms (Thompson 2005). The total area showing a Mediterranean-type climate (MTC) is about 2.3 million km 2 , with transitions toward temperate forest ecosystems (in the European mountains) and toward arid ecosystems (in North Africa and the Near East). It is not only the largest of the five MTC regions, but also the most geographically complex (with more than 40 000 km of rough coast in different peninsulas and islands) as well as the most socio-economically, culturally and politically varied. Elevations range up to 3756 m in the east (the highest peak in the Taurus mountains, Turkey) and up to 4167 m in the west (the highest peak in the Atlas mountains, Morocco). There are many volcanoes in Italy and the Aegean Islands, with frequent minor eruptions and rare major explosions. The MTC region of the basin corresponds to a narrow rim around the Mediterranean Sea (Fig. 4.1), and includes: (1) in southern Europe, most of the Iberian peninsula (Portugal and Spain), south of France, most of Italy and Greece, the coast of Croatia, Montenegro and Albania; (2) in southwest Asia (the Near East), Cyprus, Lebanon, Palestine, Israel, most of Turkey, and the coast of Syria; and (3) in North Africa (the Magreb), the north of Tunisia, Algeria, Morocco and small coastal areas of Libya. It also includes all the islands in the Mediterranean Sea. In general terms, summers are hot and dry and winters are mild and relatively wet; winters may be cold in the interior areas with a continental climate influence (e.g. central Spain and central Turkey). The configuration of seas, peninsulas and islands, and the topographic complexity of the area, produce a great regional variety of weather and climate. Rainfall ranges from semi-arid conditions (<300 mm) up to over 2000 mm, and peaks in autumn and spring (in the west) and in autumn and winter (in the east). Because of the air masses' trajectories, the wettest parts of the basin are typically the western parts of the peninsulas (Iberian, Italian and Balkan peninsulas). There are also clear gradients from the colder and wetter northwest (southern France and northern Iberia) to the hotter and more arid south and southeast parts of the basin (North Africa and the Near East). The temperature-moderating effect of the sea is highest in the west (Atlantic coast) and lessens toward the east (water temperatures rise from west to east).

Book chapter↗
USGS1967

Ground-water resources of the Pascagoula River basin, Mississippi and Alabama

Abundant ground-water resources underlie the Pascagoula River basin. These resources have been developed intensively in only a few places--namely, Hattiesburg, Laurel, Meridian, and Pascagoula. Seepage from the ground water reservoirs sustains the base flows of the Leaf, Chickasawhay, Pascagoula, and Escatawpa Rivers and their tributaries. The fresh-water-bearing section is 300 to 3,500 feet thick and is composed chiefly of sand and clay of Eocene to Recent age. Major rock units represented are the Wilcox, Claiborne, Jackson, and Vicksburg Groups and formations of Miocene and Pliocene ages. Aquifers in the Claiborne Group provide water for all purposes in the northern third of the basin. The Claiborne is underlain by the potentially important but virtually untapped Wilcox Group. Miocene aquifers are the main source of water supplies in the southern half of the basin, but Pliocene aquifers furnish most supplies in the Jackson County area at the basin's southern extremity. Much of the fresh-water section has undergone no water-supply development because of the great depth of many aquifers and the availability, at shallow depths, of supplies adequate for present needs. However, a large part of any substantial increase in ground-water withdrawal will probably come from wells deeper than those commonly drilled in the region. Ground-water levels are within 50 feet of the surface in most places, and flowing wells are common in the valleys and near the coast. Water-level declines due to pumping have become serious problems only in a few localities of heavy withdrawal. In most of these places redistribution of pumpage would alleviate the problem of excessive drawdown. Although few wells in the basin yield more than 500 gallons per minute, yields of 2,000 gallons per minute or more could be reasonably expected from efficiently constructed wells almost anywhere in the region. Total ground-water pumpage is estimated to be about 60 million gallons per day. Potential pumpage is many times that figure. Well fields capable of yielding several million gallons of water per day would be feasible in most places. The ground water is of good to excellent quality. Most of it is a sodium bicarbonate type of water. It usually is soft and has a low to moderate dissolved-solids content. Excessive iron is a problem in places, particularly where water supplies are obtained from shallow aquifers, but at least a part of the excess iron comes from corrosion of well and distribution-line fittings by slightly acidic water. Salt-water encroachment is a potential problem in the coastal area, but little increase in salinity has been observed in monitor wells in the period 1960-65. Saline-water resources are available for development at considerable depth in most of the region.

Water Supply Paper↗